1. Field of the Invention
The present invention relates to technology for generating a periodic pulse signal.
2. Description of the Related Art
The oscillator circuit of Patent Document 1 is configured such that, after charging a capacitor from a ground potential to a reference potential, a discharge switch is turned ON and the capacitor is discharged to return from the reference potential to the ground potential, and a signal, which has time required for this sequence of charging and discharging as one period, is outputted.
Patent Document 1: Japanese Patent Application, Laid-Open No. S62-272616
An ON resistance of a switch configured as a MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) or the like changes according to usage environment thereof. When the ON resistance of the switch changes, discharge time of the capacitor also changes. In the technology of Patent Document 1, the change in the discharge time directly becomes an error of the period of the output signal. When high accuracy is required in the period that it is as small as possible.